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Megawatt, 330 Hz PRF tunable gyrotron experiments

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Abstract

Repetitively pulsed and cw gyrotrons have hitherto used thermionic cathodes, whereas cold cathode gyrotrons have normally operated as ‘single shot’ devices. The novel results presented here show that cold cathode gyrotrons can be successfully pulsed repetitively. A tunable gyrotron with a pulse repetition frequency (PRF) of 150Hz is demonstrated. This system developed >4MW mm-wave output pulses at 100GHz. The gyrotron is based on a two-electrode configuration comprising a field-immersed, field emission, cold cathode and a shaped anode cavity. A superconducting magnet was used to produce the homogeneous intra-cavity magnetic field and a cable pulser was used to drive the electron beam. This pulser produced up to a (200±20)kV pulse with 10ns rise time, a 100ns flat top, a 10ns decay with a characteristic impedance of 200Ω. The energy storage capacity of the cable pulser was 35J. The charging unit limited the maximum PRF to 330Hz. Due to spark gap switching limitations 330Hz was only obtainable in 5 to 10 pulse bursts. For substantial periods of the order of 30 seconds, 100Hz PRF was achieved over an oscillating range of 28 to 100GHz and 150Hz PRF was achieved at 80GHz. No degradation effects on the mm-wave output pulse was evident due to diode recovery time throughout this series of results. A subsequent conclusion is that the diode recovery time in our cold cathode gyrotron is less than 3ms.

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7. References

  1. Sprangle P and Drobot A T, 1977, "The Linear and Self-Consistent Nonlinear Theory of the Electron Cyclotron Maser Instability,"IEEE Trans. Microwave Theory Tech. MTT-25 528–544.

    Article  Google Scholar 

  2. Lau Y Y, 1982, "Simple Macroscopic Theory of Cyclotron Maser Instabilities,"IEEE Trans. Electron Devices ED-29 320–334.

    Google Scholar 

  3. Kreischer K E and Tempkin R J, 1983 "High Frequency Gyrotrons and Their Application to Tokamak Plasma Heating,"Infrared and Millimeter Waves, Ed. Button K J7 377–485 (New York: Academic).

    Google Scholar 

  4. Shefer R E and Bekefi G, 1981 "Cyclotron Emission from Relativistic Electron Beams in Uniform and Rippled Magnetic Fields,"Int. J. Electronics 51 569–582.

    Google Scholar 

  5. Jory H, Evans S, Felch K, Shively J and Spang S, 1982 "Gyrotron Oscillators for Fusion Heating"Int. Symp. on Heating in Toroidal Plasmas, Grenoble.

  6. Brand G F and Gross M, 1989 "A Tunable Source of Linearly-Polarised, Near Millimeter Wave Radiation,"Int. J. Infrared and Millimeter Waves 10 121–136.

    Article  Google Scholar 

  7. Kreischer K E and Temkin R J, 1987 "Single Mode Operation of a High-Power, Step-Tunable Gyrotron,"Physical Review Letters 59 547–550.

    Article  Google Scholar 

  8. Gold S H, Fliflet A W, Manheimer W M, McCowan R B, Black W M, Lee R C, Granatstein V L, Kinkead A K, Hardesty D L and Sucy M, 1987 "High Power Ka-Band Gyrotron Oscillator Experiment,"Phys. Fluids 30 2226–2238.

    Article  Google Scholar 

  9. Saito H, Danly B G, Mulligan W J, Temkin R J and Woskoboinikow P, 1985 "A Gyrotron with a High Q Cavity For Plasma Scattering Diagnostics,"IEEE Trans. Plasma Sci. PS-13 393–397.

    Google Scholar 

  10. Park S Y, Vanderplaats N, Ahn S, Ganguly A K, Parker R K and Granatstein V L, 1985 "A Continuously Tunable Ka-Band Gyrotron,"IEEE Trans. Plasma Sci. PS-13 404–408.

    Google Scholar 

  11. Arfin B, Chu K R, Dialetis D, Read M E, 1982 "A High Power Gyrotron Operating in the TE04 Mode,"IEEE Trans. Elect. Dev. ED-29 1911–1916.

    Google Scholar 

  12. England A C, 1984 "Electron Cyclotron Heating Experiments in Tokamaks and Stellarators,"IEEE Trans. Plasma Sci. PS-12 124–133.

    Google Scholar 

  13. Woskoboinikow P, 1986 "Development of Gyrotrons for Plasma Diagnostics,"Rev. Sci. Instruments 57 2113–2118.

    Article  Google Scholar 

  14. Spark S N and Phelps A D R, 1991 "Tunable 35-200GHz, High Power Gyrotron,"Int. J. Infrared and Millimeter Waves 12 855–894.

    Article  Google Scholar 

  15. Humphries S, 1990 "Charged Particle Beams," (New York: Wiley).

    Google Scholar 

  16. Humphries S, 1986, "Principles of Charged Particle Acceleration," (New York: Wiley)

    Google Scholar 

  17. Blumlein A D, 1941UK Patent 589127.

  18. Somerville I C, MacGregor S J and Farish O, 1990 "An efficient Stacked Blumlein HV Pulse Generator,"Meas. Sci. Technol. 1 865–868.

    Article  Google Scholar 

  19. Cross A W, 1993 "Electron Cyclotron Maser Experiments Using Cold and Thermionic Cathodes," Ph.D. Thesis Strathclyde University.

Download references

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Authors and Affiliations

  1. Department of Physics and Applied Physics, University of Strathclyde, G4 0NG, Glasgow, Scotland

    S. N. Spark, A. W. Cross, A. D. R. Phelps & K. Ronald

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  1. S. N. Spark
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  2. A. W. Cross
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  3. A. D. R. Phelps
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  4. K. Ronald
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Spark, S.N., Cross, A.W., Phelps, A.D.R. et al. Megawatt, 330 Hz PRF tunable gyrotron experiments. Int J Infrared Milli Waves 15, 2003–2019 (1994). https://doi.org/10.1007/BF02096273

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  • DOI: https://doi.org/10.1007/BF02096273

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